(1) Field of the Invention
The present invention relates to a set of golf clubs. More particularly, the present invention relates to a set of golf clubs suitable for both yarn-wound balls and two-piece balls.
(2) Description of the Related Art
In playing golf, when an approach shot is made around the green, a precise fly distance shot is ordinarily required to facilitate a subsequent putter shot. Accordingly, a set of golf clubs for an approach shot has been developed. For example, an approach club set comprising three clubs is used. In this golf club set, the three clubs have the same length but the loft angle of the clubs is gradually increased. Namely, the first club is used for an approach shot of about 90 m; the second club is used for an approach shot of about 60 m; and the third club is used for an approach shot of about 30 m.
When a yarn-wound ball is hit by any of these approach clubs, the spin of the ball is increased in proportion to the increase of the loft angle, because of the characteristics of the ball, and therefore, a desired trajectory is obtained and the ball stop property [(run/carry).times.100 (%)] is the same for all of the clubs. Accordingly, if an appropriate club is selected, an approach shot having an intended fly distance can be obtained.
But, where a recently developed two-piece ball is used, the contact time between the ball and the club head is shorter than in case of the yarn-wound ball, and therefore, even if a club having a large loft angle is used, a ball spin proportional to the loft angle cannot be obtained. Accordingly, the ball stop property is degraded and a precise approach shot cannot be made. This phenomenon is especially conspicuous in clubs having a loft angle larger than 40.degree., and has been practically confirmed that the degradation of the ball stop property becomes more conspicuous with each increase in the loft angle. Accordingly, golfers regarding approach shots as being important dislike two-piece balls.